Question

Zinc oxide loses oxygen on heating according to the reactions.

$ZnO\overset{\quad heat\quad}{\rightarrow}Zn^{2 +} + \frac{1}{2}O_{2} + 2e^{-}$

It become yellow on heating because

• A. $Zn^{2 +}$ions and electrons move to interstitial sites and F – centres are created
• B. Oxygen and electrons move out of the crystal and ions becomes yellow
• C. $Zn^{2 +}$agains combine with oxygen to given yellow oxide
• D. $Zn^{2 +}$are replaced by oxygen.

Answer 1

Answer: (A)

$Zn^{2 +}$ions and electrons move to interstitial sites and F – centres are created

Answer 2

$Zn^{2 +}$ions and electrons move to interstitial sites and F-centres are created which impart yellow colour to ZnO.